<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .box{
            width: 200px;
            height: 100px;
            /* 圆角 */
            /* border-radius: 10px 20px; */
            background-color:green;
            /* 阴影 */
            /* box-shadow:10px 200px 0px blanchedalmond ; */
            /* 旋转 */
            /* transform: rotate(30deg); */
            /* 缩放 */
            /* transform: scale(0.5); */
            /* 位移 */
            /* transform: translate(50px,100px) scale(0.5) rotate(30deg); */
            position: absolute;
            top: 50%;
            left: 50%;
            transform: translate(-50%,-50%);
        }
        .box:hover{
            /* transform: translate(50px,100px) scale(0.5) rotate(30deg); */
        }
        /* 让一个元素在网页中水平垂直居中 */
    </style>
</head>
<body>
    <div class="box">
        <h1>hello</h1>
    </div>
</body>
</html>